Sure. I bet Apple has already sold more video chat capable phones in the US than any other company has in the past. The requirement of having an iPhone 4 at both ends is a barrier but at least it's easy to understand. Otherwise you've got to track down some model of phone with a front facing camera, ensure it can run the right software, install the software on both ends, and exchange usernames, IPs or whatever to establish the call. For most people, especially on family plans, buying the same model of phone is more realistic.